Various organic synthesis reactions using a metal complex as a catalyst have been developed and utilized for many purposes. In particular, extensive investigations on the asymmetric synthesis have recently been made and the asymmetric synthesis is utilized to synthesize physiologically active substances and also natural products.
Of metal complexes such as nickel, palladium and rhodium, a metal complex of rhodium metal and an optically active tert-phosphine is particularly known as a catalyst for asymmetric hydrogenation catalyst. For example, a rhodium-phosphine complex having 2,2'-bis(diphenylphosphino)-1,1'-binaphthyl (hereinafter referred to as "BINAP" for simplicity) as a ligand is described, for example, in Japanese Patent Application (OPI) No. 61937/80 (the term "OPI" as used herein refers to a "published unexamined Japanese patent application").
The present inventors have previously reported the formation of a optically active lactone by an asymmetric hydrogenation reaction and asymmetric dehydrogenation of prochiral or meso-type cyclic acid anhydride or diol using a ruthenium complex catalyst having DIOP (2,3-o-isopropylidene-2,3-dihydroxy-1,4-bis(diphenylphosphino)butane) as a ligand in S. Yoshikawa et al, TETRAHEDRON LETTERS, Vol. 22 (1981) 4297-4300 and CHEMISTRY LETTERS, (1982) 1179-1182. Those reactions are classified into enantiotopic differentiating reaction wherein one of enantiotopic functional groups of substrate is selectively converted, and is an interesting reaction as a catalyst reaction.
Rhodium metal is an excellent metal for complex catalyst, but the place and amount of production thereof are limited and the rhodium is expensive. Therefore, in the case of using rhodium as a catalyst, the proportion of the rhodium cost in the product cost increases and this effects the production cost of goods. Ruthenium metal is inexpensive as compared with rhodium and is expected as an industrially advantageous catalyst. However, an asymmetric ruthenium complex merely includes a few examples other than a complex of DIOP such as Ru.sub.2 Cl.sub.4 (DIOP).sub.3 and has the problems on the precision and utilization of reaction. Therefore, development of a ruthenium complex catalyst which is useful to reduce the cost of product is demanded.